Fuel injection technology is employed in most combustion systems, such as internal combustion engines or oil burners. It is well known that atomization plays an important role in combustion efficiency and pollutant emissions, specifically, that a finer fuel mist allows a more efficient burn of the fuel, resulting in more power output and fewer harmful emissions. This is attributed to a fact that combustion starts from the interface between the fuel and air (oxygen). If the size of the fuel droplets is reduced, the total surface area to start burning process increases, boosting combustion efficiency, and improving emissions.
One method of reducing the size of fuel droplets is to provide a fuel injector that utilizes a high pressure, such as up to 200 bar (20,000 KPa) for gasoline, to reduce the size of fuel droplets to 25 μm in diameter. Such an injector, however, would require substantial changes to the fuel lines in vehicles, as the current gasoline fuel lines can only sustain a fuel pressure less than 3 bar (300 KPa).
Another known method of reducing the size of fuel droplets is electrostatic atomization, which makes all fuel droplets negatively charged. The droplet size is small if the charge density on the droplets is high. In addition, since the negatively charged droplets are repulsive to each other, no agglomeration will occur. Present electrostatic atomization technology requires special fuel injectors with a very high voltage directly applied to the nozzle of each injector. The emitter cathode emits negative charges to pass the fuel to the anode, and does not move down to close the nozzle in order to stop the spray. The use of such an injector requires substantial modifications to existing vehicle fuel systems.
There exists a need to provide a method of generating a finer fuel mist from a fuel injector than is presently generated, resulting in cleaner combustion, higher power output, and higher fuel efficiency.